Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/02—Lenses; Lens systems ; Methods of designing lenses
  • G02C7/04—Contact lenses for the eyes
  • G02C7/048—Means for stabilising the orientation of lenses in the eye
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/02—Lenses; Lens systems ; Methods of designing lenses
  • G02C7/04—Contact lenses for the eyes

Definitions

• the present invention relates to a weight for a hard contact lens and a hard contact lens composite employing such a weight. More particularly, it relates to a soft or flexible weight for a hard contact lens, which is designed to be attached to the peripheral edge of a hard contact lens, particularly a multi-focal hard contact lens, to improve the stability of the lens and the comfortableness to the wearer, and a hard contact lens composite employing such a weight.
• a hard contact lens particularly a multi-focal hard contact lens
• various proposals have been made to improve the stability by various lens designs JP-A-7-239459, JP-A-6-34920, Japanese Patent No. 2539531, JP-A-4-212925 and JP-A-3-107817).
• the weight for a hard contact lens of the present invention is a weight which can be detachably attached to the peripheral edge of a hard contact lens and which has a groove of a shape corresponding to the peripheral edge of the hard contact lens, formed along the inner periphery of the weight.
• the hard contact lens composite of the present invention comprises a hard contact lens and the above weight for a hard contact lens attached to the peripheral edge of the hard contact lens.
• a weight 1 for a hard contact lens has a groove 4 of a shape corresponding to the peripheral edge 3 of a hard contact lens CL, formed along its inner periphery 2.
• the weight 1 has a crescent shape and designed to be detachably attached to the peripheral edge 3 of the hard contact lens CL.
• the length of the weight 1 can be suitably selected depending upon the type of a hard contact lens CL which depends on the shape of the cornea of a patient. However, it is preferably at a level of from 1/6 to 3/4 time of the circumferential length of the above mentioned peripheral edge 3. If it is less than 1/6 time of the circumferential length of the peripheral edge 3, the weight 1 is likely to be easily detached from the hard contact lens CL, and if it exceeds 3/4 time, the stability of the hard contact lens tends to be poor.
• the above weight 1 is detachably attached, whereby cleaning, disinfection or replacement of the lens can easily be carried out.
• the hard contact lens to be used in the present invention a common commercial product can be used.
• a hard contact lens with Dk/L (oxygen permeability/thickness of the lens center (cm)) being at least 20 ⁇ 10 -9 [(cm/sec) ⁇ (mlO 2 /(ml ⁇ mmHg))] which is able to supply adequate oxygen to the cornea.
• the material of the above weight 1 is preferably a soft material to improve the comfortableness to the wearer.
• a soft material may, for example, be a copolymer of at least one component selected from water-containing materials, such as a hydroxyalkyl acrylate or a hydroxyalkyl methacrylate, such as hydroxyethyl acrylate or hydroxyethyl methacrylate; an N,N-dialkylacrylamide and an N,N-dialkylmethacrylamide, such as N,N-dimethylacrylamide; and an N-vinylactam such as N-vinylpyrrolidone, a polysaccharide such as dextran, cellulose, starch or gum arabic, crosslinked by e.g. sodium hyaluronate or chondroitin sulfuric acid, or a no-water containing material such as silicone rubber, urethane rubber, an acrylic copolymer or a methacrylic copolymer.
• water-containing materials such as
• the weight preferably has a means for gradually releasing a drug.
• a means for gradually releasing a drug may, for example, be one having a drug coated on the weight, or one having a drug impregnated in the weight.
• the impregnation method may, for example, be a method of directly immersing the weight in the drug, a method of coating the drug on the weight, a method of incorporating the drug in the above mentioned soft material, followed by molding to prepare a weight, or a method of adding a blowing agent to the above mentioned soft material, followed by molding to obtain a weight, whereupon the drug is impregnated thereto by vacuum.
• a pocket 14 capable of retaining a drug, which is formed between the peripheral edge of the hard contact lens and the inner periphery 12 of the weight 11 i.e. at the bottom of the groove 13, may be employed.
• the drug in this pocket 14 is designed to ooze out from a clearance between the hard contact lens and the weight by a capillary action to the cornea.
• the above drug may, for example, be a common ophthalmic agent as disclosed in e.g. JP-A-8-104636, JP-B-59-7684 or JP-A-7-503974, such as lacrimation increasing agent, a cell propagation accelerator, a suppressant against increase of the corneal thickness, a mydriatic, a miotic, an antibiotic, a fungicide, an antihistamine, an anti-inflammatory agent, an anticholinergic, an antiglaucoma compound, an anthelminthick compound, an antivirus agent, a carbonate dehydrarase inhibitor, an antifungal agent, an anaesthetic agent, a peptide or a protein, which is used as a preventive or curing agent for an eye trouble (such as inflammation) or wound, a diagnostic agent or an immunosuppressive agent.
• a common ophthalmic agent as disclosed in e.g. JP-A-8-104636, JP-B-59-7684 or JP-A-7-50
• the weight has a crescent shape.
• the present invention is not limited to such a shape.
• the weight may be made to be a weight 21 having an anchor shape, which has a swelled portion 20 formed at the center. By providing such a swelled portion 20, the weight 21 can be made to be less likely detached than the above weight 1.
• the obtained composite was put on an eye of a person.
• a weight was prepared in the same manner as in Example 1. Then, 0.2 ml of an ophthalmic solution made of a 5% hydrochloric acid calteorol aqueous solution was dropped to the weight by a syringe, and then the weight was attached to the same lens as in Example 1.
• the weight can be attached to a commercially available hard contact lens, whereby stability of the hard contact lens and comfortableness to the wearer can be improved at a low production cost. Further, by gradually releasing a drug from the weight, it is possible, for example, to reduce the intraocular tension.

Landscapes

• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Eyeglasses (AREA)
• Materials For Medical Uses (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=15938205

Family Applications (1)

Country Status (4)

Cited By (2)

Families Citing this family (3)

Citations (6)

Family Cites Families (4)

• 1997
  • 1997-06-27 JP JP9172239A patent/JPH1124009A/ja active Pending
• 1998
  • 1998-06-03 US US09/089,500 patent/US6042229A/en not_active Expired - Fee Related
  • 1998-06-25 DE DE69814531T patent/DE69814531T2/de not_active Expired - Fee Related
  • 1998-06-25 EP EP98111751A patent/EP0887687B1/de not_active Expired - Lifetime

Patent Citations (6)

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